Earthquake shakes county

A high Sierra earthquake shook western Nevada County shortly before noon Sunday.

Centered about seven miles southeast of Truckee, the 4.8-magnitude rumbler was felt as far away as Sacramento, said U.S. Geological Survey spokeswoman Stephanie Hanna.

A dozen aftershocks, all weaker than 2.2, kept mountain residents shaking until late Sunday afternoon. The aftershocks are normal and do not portend a massive quake, Hanna said.

There were no immediate reports of damage or injuries.

Robyn Morgan, 12, had never felt an earthquake before, but when the windows and a bathroom mirror starting swaying, Morgan realized she had felt a "baby earthquake" in Grass Valley.

Savanna Engstrom, 17, watched the tremor move from one side of her Cascade Shores house to the other.

"The whole house was creaking. It was kind of scary," Engstrom said.

Nevada City resident Noah Thompson was lying on the floor of his Park Avenue house when he heard a strange noise. About 10 seconds later, the floor rolled and he heard a small thump.

"It wasn't very spectacular," Thompson said.

The quake failed to wake Lindsay Burgess, sound asleep in her residence near Dorsey Drive.

The quake and its several aftershocks struck five miles underground, just east of a known but unnamed fault east of Truckee, according to the USGS.

"It is not so much damaging as it is a wake-up call," Hanna said, pointing out that earthquakes have struck the Truckee area before and they will again.

In 1914, two sizable tremors - 5.5 and 6.0 - rocked the Truckee region.

Earthquakes are measured using logarithms. For example the 1989 Loma Prieta quake in the Bay Area rated a 7.1, more than 100 times as large as Sunday's quake.

During an earthquake, stay away from windows, power lines, trees and anything else that might fall on you.

For a real-time earthquake forecast, visit http://pasadena.wr.usgs.gov/step/

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To contact staff writer Becky Trout, e-mail beckyt@theunion.com or call 477-4234.